Method of manufacturing electric conductors



-luly 24, 1923- 1,462,580

` R. RDr-:NBERG ET AL.

METHOD OF MANUFACTURING ELECTRIC GONDUCTORS Filed Dec. 27, 1920 2 Shee'ts-Sheet 1 -vvvv 1 Wai R. RDENBERG ET AL METHOD OF' MANUFACTURING ELECTRIC CONDUCTORS July 24, 1923- Filed Dec. 27. 1920 2 Sheets-Sheet 2 E@ 229,9

Eig. M

Patented July 24, 1923'.

UNITED STATES PATENT OFFICE.

mmmonn automne, or amm-GRUNEWALD, AND ADoLF FINCKBETN, or cnam LorrENnUne, GERMANY, AssmNons 'ro SIEMENS-scauoxnnrwnnxn G11-snm.- scmurr mr nnscnnnxrnn Immune, or SIEIENSTADT, Nm3 BERLIN, enn- HANY, A GERMAN CORPORATION.

METHOD OF MANUFACTURING ELECTRIC CONDUCTORS.

Application filed December 27, 1920. Serial No. 433,453.

To all 'whom 'it may concern.'

Be it known that we, REINHom RDEN- BERG and AnoLr FINCKBEIN, citizens of the German Empire, residing at Berlin-Grune- I wald, Germany, and Charlottenburg, Germany, respectively, have invented certainv new and useful Improvements in Methods ofManufacturing Electric Conductors (for which we have filed ap lications in Germany Deo. 14, 1917, and ec. 29, 1917 Huni ging, hov. 13,1918, and Nov. 14,1918; Englan July 8, 1920, and July 9, 1920; Sweden, Jan. 7 1920; Switzerland, Jul 23, 1920; and Austria, Aug. 27, 1920), o which the 16 following is a specification.

Our invention relates to a method of manufacturing electrical conductors. For many purposes and more particularly, for conductors carrying hea currents, it 1s necessary 20 to employ multip e conductors. Now, the manufacture of such conductors is always rendered difficult wherever the cross-sectional shape deviates from a round shape, for the reason that such a deviating form L j cannot be readily attained by carrying out of the customary twisting operation on the twistin machines.

Our lnvention refers in particular to an improved method of manufacturing multiple conductors, which will be found to excel by reason of its extraordinary simplicity and l which will prove suitable for conductors of any desired size, only very simple machines being required to carr our improved method into effect. The mu tiple bars produced according to this improved method are rendered veryl stii and are moreover but to a very slight degree liable to warp and bend during the process of manufacture, an-

incident otherwise easily occurring whenever a conductor twistedin the manner hitherto used is being subsequently shaped into loops 'by a premg operation.

We will now proceed-to more fully describe our improved method with reference to the drawings annexed to this specification and forming part thereof. In these drawings `igures 1a and 1b show a front view and cross-sectional shape, respectively, of a plurality of single conductors wound to a coil,

Figure 1c shows the cross-sectional shape 0f the coil after it is flattened,

Figures 2a 'and 2b show a side view and cross-sectional shape of the coil after having beenstretched,

Figure 3 shows the composite conductor after its'completion,

Figures 1g-693B, show side views and cross-sectional shapes respectively, of sev. eral modified forms of execution.

Figures 7 and 8 show sectional views of thel original coil before and after flattening, an

Figuresv 9 to 13 show-side views and crosssections, of a composite conductor produced in accordance with our improved method.

In carrying out the method in accordance with our invention, the individual conductors forming the composite conductor are first of all wound either together or singly to form flat, cylindrical coils wit-h their turns as close together as possible. The manufacture of these coils is carried out by any one of the customary methods, for example by winding the individual wires of the composite conductor about two pins ixed to a support. In Figures 1a and 1b are shown a series of single conductors a b o d, etc. wound to a coil in the manner aforesaid. Now whenever it becomes necessary to twist these conductors together in order to form a flat composite conductor the thickness i (Figure 1) of which is smaller than the thickness k of the coil (Fig. 1b), then this latter may be simply compressed until the desired latness illustrated by Figure 1c is obtained. There is thus rovided a ready means of adjusting the thic ness of the composite conductor accordin to requirement pff simply71 lpressing toget er the dat coil.

ereupon1 t e turns of the coils are stretched (Figure 2a) to such an extent until the coils thus drawnapart attain the desired height of the composite conductor asre uired to fit for instance an armature slot igure 2).

After all the conductors comprlsing the composite conductor have been manufacent, an internal space, the dimension of which is amply suicient for the insertion of an insulation serving to suitably insulate from each other the crossing conductors of the two sides of the com osite conductor or bar. On the other han if preferred, the internal section ofthe bar may be made suflicientl lai' e to act as a-channel for the introduction o cooling air. In such a case, the coil need not be pressed together, but may be for instance directly wound on a mandril or other suitable means leaving a channel of the desired size.

Now when stretching the coils, in order to give them for instance lthe sectional shape disclosed in Figure l", and to obtain the desired pitch on either the broad sides or the narrow sides of the finished conductor, there may be exerted a reater amount of pull on the long sides o the fiat coil and but a slight amount of pull on the sliort arcs comprising the narrow sides (Figure 1) or else the operation may be reversed, and the greater pull be exerted on the said 'short sides of the coils. Several modifications in which this effect may be obtained are illustrated in Figures 4 to 6. Figure 4b shows the turn of a coil having an internal width 'p l. On stretching the turns to obtain the profile of the slot in which it is to be disposed,

it must be stretched as disclosed in Figure l 4, and accordingly the internal section of the conductor in Figure 4", may according to the pull exerted on the narrow arcs of the turns, be reduced to the width m of Figure 4". If it be further desired to secure the like internal width m of the finished bar for coils having turns of larger pitch (Figure ...5") then, in stretching the turns in order to obtain the cross-section required for the bar, a more powerful pull must be exerted on the small arcs of sides of the individual coils,

so that the turns assume a pitch such as is shown in the plan view of the bar in Figure 5. It will therefore be necessary to initially allow for the narrow side of the coil an arc of such a radius, respectively, such a length,. as will allow the securing of the desired pitch for the narrow sides of the finished bar. If, however, a slighter pull be exerted on the turns of a coil, of similar initial shape, then .from such a coil having the section shown in Figure 6", when stretched to conform with the desired profile formation of the composite bar (Figure 6), there will result an internal width ln for the finished bar as shown in Figure 6 which is considerably greater than the internal section m as disclosed by -Figure 5. A considerable amount of cooling air may (pass through a hollow conductor of this escription. The cross-section of the channel formed in the hollow conductor may consequently likewise be shaped as required b suitably dimensioning the narrow side o the initial coil.

This method of manufacture in accordance with my invention affords a number of im* portant advantages. For instance, by first of all making a fiat cylindrical coil there is secured the advantage of all individual wire elements of which the finished conductor bar is composed being alike, so that after having been stretched 'to a like degree and havingi been subsequently nested into each other, there will result a conductor bar of uniform structure throughout, possessing no inclination to bending or warping in any direction whatsoever. Owing to the uniformity in form of the individual elements, the latter may be oined closely to each other even where the cross-sectional dimensions are but slight. The bar thus completed may then be compressed in any manner to at tain the desired shape. By making the conductor bar out of a pluralit of individual elements, there is the ad( itional possibility afforded of insulating its constituent conductor elements relatively to each other to a satisfactory degree, since there now no longer exists the necessity of introducing the insulating material by more or less complicated devices and methods into a conductor composed of a plurality of individual conductors. It will also be found, that our improved method of manufacture is applicable to conductor elements of any desired cross-section.

Wheneve'r our Iimproved method is employed for producing flat conductors of the type described, for example, in Pichelmayers Handbuch der Elektrotechnik, Ed. 1908, P. 420, for use in large alternating current machines, a bar is obtained by our method which is exceedingly suitable, in particular for machines having a heavy current output, a considerable length of rotor and altogether large dimensions.

In Figure 7 is illustrated an original or initial coil element constituting afiiat wire Wound into a flat cylindrical coil. Now if this coil, after having been further flattened by compression (should this be required) to the shape disclosed by Figure 8, be

stretched by seizing it by its ends without, however, taking anyother precautionary measures, such as gri rings, or the like, there will be produce a stretched conductor of the shape shown by the three conductors in Figure 12. He're three conductors produced from three original coils ofthe type illustrated in Figure 7 are assembled as a portion o f -the bar to be produced, of a cross-section shown in Figure 11, to fit a given slot.

It will be noted that in this arrangement, the imaginary planes in which the short arcs 'u and 'v are located, are at an angle to the imaginary planes, in which the straight ortions s and t are located; This form-of individual conductor element when assembled into a bar as shown in Figure 12, will produce. small interstitial spaces between the arc portions u .and e of adjoin, ing elements, as shown in Figure 12, owing to the raising and crowding of material at the inside of the arc. These spaces represent in the completed conductor bar portions, not. filled with useful conductor material.

These spaces may likewise be utilized in accordance with our invention, permitting the use of practically the entire, available cross-sectional area of the slot, if the coil be stretched in such a manner that the short side uor fu, respectively of the coils (Figure 7 a're located within the plane in which one or the other adjoining long side s or respectively, is located. This object may be accomplished by securing the short sides of the coil, during the stretching operation, for instance by means of a pair of at-nosed pliers, so that the arc ortion is held in the plane of one of the adiioining long sides of lthe coil. This will result in a shape of stretched coil shown in Figu're 9, a number of such coil elements being shown assembled `in Figure 10, by nesting the individual coil elements into each other to form a finished conductor of the height shown by the dot and dash lines in Figure 10 and of a crosssectional contour shown in Figure 11.

It will be noted that in the arrangement according to Figure 10, the short arcs of the turns are far more closely disposed to each other than in the arrangement according to Figure 12. The strength of the conductor and the utilization of the available space are thus increased in a simple manner.

A special advantage of the improved arrangement resides lin the feature that the short arcs fu, of the coils, (which for instance in Figs.'8 to 13 constitute the small sides of the coils) extend within the assembled conducting bar in a direction transve'rsely to the axis of the bar and thus to the axis of the slot, so that the slot field is. able only to a small degree to create eddy currents.

Arrangements with round conductors shown in 'Figures 4c, 5c, 6 'may also be made with flat conductors such as illustrated in Figures 7 to 13. It is possible in stretching t e individual coils, to also stretch the short arcs u, v of Figure 12, so that they assume a similarly oblique position relativeto the conductor bar axis as is shown in l higures 4 5, 6*l in case of round conductors. In tl'i varcs do not have too small a radius (for instance Figures 8 and 11 would be unsuited fo'r this purpose) but one of substantial size for instance as shown in Figure 7, oi" else they may be given the form shown in` Figure 13.

This arrangement, however, shifts the arc portions into a position substantially longi-v tudinally of the slot, such as in case of round conductors arranged according to Figures 4, 5*?, t", and therefore the slot field is more likely to generate eddy currents than in case of the modifications according to 4Figures 10 and 12.- j

lso in this case like Yin those'of the coils described with reference to Figures 1 to 6, the manner of proceeding may consist in winding a coil in this ease however of flat stock, shown in Figure 7, and compressing it if necessary, to such an extent that an internal space remains of a size required for each particular case, suitable, for instance, for the insertion of a longitudinal insulation z, such as shown in Figure 11, or for the formation of a channel k, such as illustrated by Figure 13 and adapted to be traversed by cooling air.. In this latter case the compressin of the initial coil may even be omitte if, as lwas already mentioned hereinbefore, the coil is wound from the outset over a mandril or given b any other suitable means the internal width'required for the cooling channel.

We claim 1i The method of producing multi le conductor bars, consisting in winding t e constituent conductor elements separately as fiat coils, stretching the windings of said coils apart until the' desired pitch has been obtained and in nesting said stretched coil elements into each other to form the bar.

2. The method of producing multiple conductor bars, consisting` in winding the lconstituent conductor elements separately as flat coils compressing said coils to the desired thickness of the finished bar, stretching the windings of said compressed coils apart until the desired pitch has been obtained and in nesting said stretched coil elements in to each other to form the bar.

3. The method of producing multiple conis case 'it is assumed that these.

ductor bars, consisting in winding the con- 4. The method of producing multiple conductor bars, consisting in winding the constituent conductor elements separately as flat coils, stretching the windings of said coils apart until .the desired itch' has been obtained and in nesting sai stretched coil ele- 4ments into each other to form the bar, the

length of the short sides of said flat coils being suitably chosen to obtain the desired pitch of said sides relatively to the axis of the finished bar, and to cause the formation of a, longitudinal channel inside of the iinished bar.

5. The method of producig multiple con-- REINHOLD RDENBERG. A DOLF FINCKBEIN. 

